1. Field of the Invention
This invention relates to retractors used in surgical procedures and more particularly relates to a retractor for lumbar spinal fusion that includes adjustable length retractor blades and guides for positioning fixation screws and a light pipe.
2. Background Information
In a surgical procedures trauma to the patient and damage to the tissue needs to be minimized as much as possible. To achieve this result surgeons try to keep incisions as small as possible when performing surgical procedures such as lumbar spinal fusions by making a midline mini-incision. However, it is necessary that the surgeon performing the delicate surgery to have a clear view of the operating field. A variety of retractors are available to keep an incision open and provide a clear view of the field of the operation.
Such surgical retractors are particularly important in performing spinal fusions, and particularly lumbar disc operations where the surgical procedure is provided by an anterior/lateral approach through the abdomen. One such retractor is disclosed and described in U.S. patent application Ser. No. 08/935,761, now U.S. Pat. No. 5,944,658 of T. Koros et al filed Sep. 23, 1997 and incorporated herein by reference. This application discloses a retractor in which the surgeon makes a small incision in the abdomen to view the region of the vertebrae where the lumbar disc operation is to be performed. The retractor disclosed is inserted in the incision to hold organs, muscles, arteries and other tissue out of the way and provide a clear view of the spinal region being operated on.
Another important feature of the retractor is allow insertion of retractor blades without damage to the tissue. To achieve this the lumbar spinal fusion retractor and distractor system of the above mentioned application is constructed to displace only a small volume when inserted in the incision before it is opened, or "spread" to provide a clear view of the operating field.
Another important feature of the retractor is that it stay in position in the difficult lumbar fusion. To prevent such occurrences, fixation screws are provided that pass through blades of the retractor and are fastened to adjacent vertebra.
However, another common problem with this retractor is that no single length of blade that is suitable for all patients. Therefore several different size blades must be provided for different patients. This requires up to at least twelve different blades being provided and sterilized for an operation. The size and length of the blades can vary anywhere from 10 cm to 24 cm. Also when the retractor is placed in the patient, the surgeon may have to experiment with different length blades until he gets the right length. This increases the length of the operation and the danger of increased trauma to the patient. It would be advantageous if a single blade could be used having a length adjustment allowing rapid positioning and placement.
Another important aspect of the retractor is the provision of viewing an extremely small area during this surgical procedure to minimize the size of the incision. Thus it is apparent that a very clear view of the operating site must be provided. To accomplish this light pipes are used on the end of long cables that provide intense illumination of the surgical site. Since the volume of the area being operated on is small, the inclusion of a light pipe in the patient creates additional problems of interference with the surgical procedure.
It would therefore be advantageous if a method could be provided to accommodate a light pipe and providing intense illumination while avoiding interference with the surgical procedure.
It is therefore one object of the present invention to provided an improved retractor having retractor blades that are adjustable in length.
Still another object of the present invention is to provide a retractor with an adjustable length blades that remain fixed at an adjusted position.
Still another object of the present invention is to provide a retractor having an adjustable length blades having guides for fixation screws for attaching the retractor to the vertebrae of the patient.
Still another object of the present invention is to provide a retractor having adjustable length retractor blades with stops to prevent the adjustable length blades from being dislodged from the retractor.
Yet another object of the present invention is to provide a retractor having adjustable length retractor blades that are held in place at their adjusted position by frictionally engaging leaf springs.
Yet another object of the present invention is to provide adjustable length adjustable blades having a guide for receiving and holding a light pipe.
Yet another object of the present invention is to provide a retractor having adjustable length blades with guides for attaching multiple fixation screws to vertebra.
Other objects and advantages of the invention will become more apparent from the following portion of this specification, and the accompanying drawings.